Flash Required: bad idea.  Seriously, Flash has been so over-abused by intrusive advertising, that I have it disabled it on my computers.  When I see a website that REQUIRES it, I simply leave.  Really.

You can still use Flash, just make sure that you also have a very-easy-to-find non-Flash version.  Or only use Flash for some of the more gratuitously unnecessary parts of the website, which people won't really miss seeing.

Just some friendly advice.